They recommend silicon for the tracks that the clamps travel along and rubbing alcohol for the teeth of the clamps. That's it. They didn't say anything about oil or WD40. Ask Mark what's going on. Tightening the clamp base solved the problem for me.

i don't think he's having an issue w/ the BASE CLAMP. his problem is w/ the 3 or 5 tooth STRING CLAMP. OP is saying the clamping action on one string clamp is smooth when he clamps down on the string, while the action of the other is rough.

OP, is this the part you're having problems with? one clamps smoothly while the other is gritty?